The present invention relates to a primary component of a personal fall arrest system, namely, the harness. The harness, often called a full body harness, is designed to safely support a person being lifted or lowered as well as to sufficiently distribute the fall arrest forces across the wearer""s body, thereby reducing injury from a fall if the harness is properly used as part of a fall arrest system.
Full body harnesses are widely used for lifting and lowering individuals in dangerous situations and as a primary component in a personal fall arrest system. They can also be used for work positioning, travel restriction, ladder climbing, rescue retrieval and evacuation. While these harnesses are used mainly in an industrial setting, and particularly the construction industry where the likelihood and danger of falls from heights is both numerous and significant, a full body harness can be used in various other applications in which total suspension and support of the body must be ensured, either expectedly or unexpectedly.
Various full body harnesses are shown on pages 6-19 of the MSA Fall Protection Catalog [Vol. 4-2001/2002], including the FP Pro(trademark) Harness, FP Trades(trademark) Harness, FP Rescue(trademark) Harness and FP Classic(trademark) Harness. Such harnesses typically include adjustable shoulder straps which can be guided in a crossed fashion through a generally rectangular shaped pad formed on a rear part of the harness which is worn on a person""s back and is often called a rear pad or back pad. Generally, the shoulder straps are made from pieces of straight webbing.
In the FP Pro Harness, as described in U.S. Pat. No. 5,957,091, the shoulder straps made from straight webbing continue forwardly over the shoulders and adjustably attach to each other via a pair of metal hip plates. Two leg straps are also adjustably attached to the hip plates and wrap around the legs of the wearer. The leg straps are also made from pieces of straight webbing.
The FP Classic(trademark) Pullover(copyright) Harness is more particularly shown and described in U.S. Pat. No. 4,712,513. This harness does not require the pre-adjustment of numerous elements to a particular individual but can be adjusted simply and quickly with a single adjustment for practically all sizes of individuals for whom the harness is intended. However, it also uses only pieces of straight webbing.
While all of the above-mentioned harnesses meet the applicable safety requirements, it would be desirable to improve their comfort without reducing the quality and versatility of these harnesses.
Generally, the present invention is a full body harness which utilizes pieces of curved webbing. Preferably, the harness comprises: a pair of shoulder straps (preferably adjustable) comprising curved webbing; a subpelvic strap; a pair of leg straps (preferably adjustable); a back pad; a shoulder strap retainer (preferably a front pad or a chest strap); and a pair of leg buckles. While the curved webbing is preferably utilized in the shoulder straps, it could also be utilized in other parts of the harness such as the leg straps or the subpelvic strap.
The present invention provides a unique, versatile and lightweight full body harness which still meets or exceeds most applicable requirements, including ANSI Z359.1, ANSI A10.14, CSA Z359.10 and OSHA, while improving its comfort. The full body harness of the present invention is uniquely designed to contain the torso of a wearer, position it in an upright position and distribute fall arrest forces to the thighs, chest and shoulders of the wearer in the event of a fall. The harness of the present invention is intended to be used in personnel fall arrest systems as well as in work positioning. The harness preferably comes in the Pullover(copyright) model and the Vest-Type(trademark) model with several sizes in each model, including extra small, standard, and extra large. Additionally, the full body harness of the present invention provides improved comfort, for example, by preventing the shoulder straps from riding up onto the neck of the wearer.
The full body harness of the present invention preferably utilizes five pieces of webbing, namely, two shoulder straps, two leg straps and a subpelvic strap. Preferably, the shoulder straps of the harness comprise curved webbing. Preferably, the pieces of curved webbing are preformed into a slightly curved shape to provide enhanced wear relief from the webbing when worn in sensitive areas. The present invention can also include an improved back pad, a standard shoulder strap retainer such as a front pad or a chest strap, and a pair of leg buckles. The improved back pad preferably has a generally X-shaped design (with the upper arms of the X being longer than the lower arms which helps keep the shoulder straps from riding up onto the neck of the wearer. Each leg buckle is designed to facilitate quick connection and disconnection without permitting accidental disconnection.
Preferably, the safety harness of the present invention utilizes curved webbing in places where narrow webbing is used or in sensitive places such as the user""s neck, torso, waist, groin or buttocks. The curved webbing provides enhanced wearer relief from webbing located in or near sensitive areas, when under low tension, without reducing the high tension performance of the webbing. For example, using curved webbing to form the shoulder straps prevents them from riding up onto the neck of the wearer.
The curved webbing can be formed by various methods that cause a distortion in the linearity of the webbing when under low tension. Such methods can include the use of elastic or crimped stuffer yarns, calendering, as well as special weaving. Another method used to obtain the curved webbing is to apply a heatset to the straight webbing. By applying heat, a shape can be formed in the webbing that creates the desired curvature.
Heatsetting is the preferred method of creating the curved webbing used in the harness of the present invention since it requires only one size of webbing from the mill/factory for use in all sizes of the harnesses. The straight webbing is placed into a preformed mold or channel of a heatsetting machine that has the desired shape or curve for the finished webbing. The machine applies heat (preferably dry heat) to the webbing until it is just below its melting temperature. For certain polyester webbing, this is around 470xc2x0 F. For other materials, the temperature will be different. The webbing is held in the preformed channel that contains the desired curvature. As the webbing nears the melting point, it takes on the shape or curvature of the channel in which it is held. After the webbing is heated and takes on the desired curved shape, the webbing is cooled while still being retained in the channel or mold. After cooling, the curved webbing has the same feel as the non-curved webbing. Applicants have found that the heating/shaping process does not adversely affect the strength of the webbing or how the webbing performs in a dynamic fall.
The present invention also comprises an improved back pad that spreads the shoulder straps away from the neck area of the wearer by aiming the straps away from the center of the body. The spreading back pad of the present invention achieves this result through the location of the slots at the top of the back pad relative to the slots at the bottom of the back pad. Preferably, the slots at the top of the back pad are slightly offset upwardly and outwardly from the centerlines of the back pad relative to the slots at the bottom of the back pad thereby forming a generally Y-shaped configuration. Alternatively, this configuration may be described as generally X-shaped with the upper arms of the X being longer than the lower arms.
Other details and advantages of the present invention will become apparent as the following description of the invention proceeds.